The days of superstar athletes being unwilling to speak their minds for fear of damaging their earnings or reputation appear to be at an end.

President Trump decided to take on some of the biggest names in pro sports on Friday and Saturday, including Stephen Curry of the Golden State Warriors. Unlike Michael Jordan, who famously did not want to offend anyone who might buy his signature sneakers, players around the country’s leagues have begun firing back.

Mr. Trump has found himself criticized by players in both the N.F.L. and N.B.A., with the focus on two specific areas: The protests of the national anthem at N.F.L. games, and the open question of whether or not the Warriors would visit the White House after their recent N.B.A. championship. Neither topic is particularly fresh, but with Mr. Trump urging N.F.L. owners to “fire” the protesting players, and tweeting that the Warriors were no longer invited for a visit, the embers on both issues have been thoroughly stoked.

Mr. Curry made some waves at the Warriors’ media day on Friday when he said of a potential White House visit: “I don’t want to go. That’s really it. That’s the nucleus of my belief.”

The debate over any visit proved irrelevant, however, when Mr. Trump weighed in on the subject with a tweet on Saturday.

The response from players was swift. Several players in both leagues condemned the announcement, in a throwback of sorts to the days when political statements by star athletes like Muhammad Ali, Bill Russell, Tommie Smith and John Carlos were more common. Potentially the boldest response to Mr. Trump came from the Warriors’ chief rival, LeBron James of the Cleveland Cavaliers:

Mr. Curry was also supported by Chris Paul, the Houston Rockets point guard, who also happens to be the president of the N.B.A.’s players association.

While Mr. Curry has yet to respond, his teammate, the outspoken Draymond Green, unsurprisingly weighed in.

As an organization, the Warriors were far more politically reserved than Mr. Green, saying in a statement, “In lieu of a visit to the White House, we have decided that we’ll constructively use our trip to the nation’s capital in February to celebrate equality, diversity and inclusion — the values that we embrace as an organization.”

No stranger to controversy involving Mr. Trump, Jemele Hill, the ESPN host, also supported Mr. Curry. Ms. Hill was recently embroiled in a debate centered on her reference to the president as a white supremacist, and his office’s call for her firing.

Mr. Trump has found just as swift a response from players and personalities connected to the N.F.L. over his comments about players like Colin Kaepernick who have sat or knelt during the national anthem to protest the treatment of black people by the police. At a rally in Alabama, Trump said: “Wouldn’t you love to see one of these N.F.L. owners, when somebody disrespects our flag, to say, ‘Get that son of a bitch off the field right now. Out. He’s fired! He’s fired!’”

Among the players to respond to Trump’s statements was Chris Conley, a wide receiver for the Kansas City Chiefs.

In a series of strongly-worded tweets, Martellus Bennett, a tight end for the Green Bay Packers, said he was fine with being fired for what he believes in and rejected the labels put on players by the president.

Richard Sherman, the outspoken Seattle Seahawks cornerback, said:

The topic seemed to elicit opinions from all over, with Sean Combs, the businessman and music mogul, asking N.F.L. players to make a statement before tomorrow’s games.

And none other than Ed Asner, the 87-year-old actor, tackled the subject.

Amid all the chaos online, Ayesha Curry, the wife of Stephen, took the high road in the matter, refocusing the discussion on bigger events going on around the world.